A real-time protocol (RTP) provides end-to-end network transport functions suitable for applications transmitting real-time data, such as audio, video or simulation data, over multicast or unicast network services. RTP does not address resource reservation and does not guarantee quality-of-service for real-time services. The data transport is augmented by a control protocol (RTCP) to allow monitoring of data delivery in a manner scalable to large multicast networks, and to provide minimal control and identification functionality. RTP and RTCP are designed to be independent of underlying transport and network layers. Presently, monitoring systems are unable to determine worst-case RTP streams at an arbitrary point within a network to monitor quality of a voice call or quality in data transmission, for instance. One of the problems involved in determining the worst-case RTP streams is that of available processing power to examine and analyze every RTP stream transmitted between endpoints. For instance, at the arbitrary point within the network, thousands of RTP streams pass through, thus, analyzing each RTP stream that passes through the arbitrary point cannot be done by existing processing technology.
To date, analyzing the worst-case RTP streams has been performed using two approaches. The first approach examines the RTCP RR (receiver report) packets and RTCP SR (sender report) packets, which occur at a much lower rate (i.e., 5% or less of a bandwidth of the RTP stream). However, the RTCP RR packets include jitter and packet loss information as seen from the endpoints of the network, which prevents determining where a problem may be originating within the network. The jitter and packet loss information are not acceptable because a user examining the RTP streams is unable to determine at which point within the network a problem is originating. The second approach monitors the RTP packet streams. With no selection criteria, the RTP streams are selected on a first observed order. While the second approach may provide accurate information, there is insufficient processing power available to monitor all the RTP streams.